docs(workbench): add wave-1 brief pack for Phase 1 polish
Four parallel-safe briefs covering Chat/Proposals/Replay/Evals polish,
each with operator assignment, dispatch line, doctrine refs, owned-files
scope, acceptance criteria, and validation commands.
Operator assignment:
- 1a Chat polish -> Opus 4.6 (surface contract sensitive)
- 1b Proposals polish-> Sonnet 4.6 (tight-scope lifecycle)
- 1c Replay polish -> Gemini 3.1 Pro (cross-file presentation)
- 1d Evals polish -> GPT-OSS-120B / Copilot (mechanical)
All four are dispatchable simultaneously. No order dependency.
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